What Hill discovered is that all these individuals realized the importance of surrounding themselves with people smarter than they were.

I couldn't agree more. All of us together are a lot smarter than any one of us. Which leads to some of the best career advice I can give you: Networking is a skill you must develop.

If I had to name the single characteristic shared by all the truly successful people I've met over a lifetime, I'd say it is the ability to create and nurture a network of contacts. A network replaces the weakness of the individual with the strength of your network. You don't have to know everything as long as you know the people who do.

A network can enrich your life. It can help you help others. A network improves your job security. If you build a network, you will have a bridge to wherever you want to go. So if you are ever up the proverbial creek, with a network you will always have a paddle.

Just remember, the more you exercise your networking muscles, the stronger they get and the easier networking becomes.

What other career advice can you benefit from?

You can't forget the most important five-letter word in business — trust. How about integrity, reputation and treating everyone with respect? I might add that you have to continue your education, because you should be in school all your life. I've written extensively about all these topics, and will continue to hammer them home because they are the difference between a job and a successful career.

And because I follow my own advice and continually study the brilliant thoughts of others, I'll share words of wisdom from some of the world's most successful people:

Steve Jobs, co-founder of Apple Inc.: "When I was 17, I read a quote that went something like: 'If you live each day as if it was your last, someday you'll most certainly be right.' It made an impression on me, and since then, for the past 33 years, I have looked in the mirror every morning and asked myself: 'If today were the last day of my life, would I want to do what I am about to do today?' And whenever the answer has been 'no' for too many days in a row, I know I need to change something."

Michael Dell, founder of Dell Inc.: "Try never to be the smartest person in the room. And if you are, I suggest you invite smarter people, or find a different room."

J.K. Rowling, author of the Harry Potter novels: "Had I really succeeded at anything else, I might never have found the determination to succeed in the one arena I believed I truly belonged."

Carlos Slim Helu, telecommunications magnate who is considered the world's richest person: "I don't want to live thinking about how I'll be remembered."

Warren Buffett, chairman of Berkshire Hathaway: "I don't look to jump over 7-foot bars. I look around for 1-foot bars that I can step over."

Mark Zuckerberg, co-founder of Facebook: "If we want to have the biggest impact, the best way to do this is to make sure we always focus on solving the most important problems."

Cathie Black, former president of Hearst Magazines: "Most people see taking risks as opening themselves up to unnecessary, maybe even dangerous chances. But the truth is, avoiding risks won't keep you safe, nor will it guarantee a smooth ride at work or in life."

Richard Branson, founder and chairman of Virgin Group: "My mother always taught me never to look back in regret but to move on to the next thing. The amount of time people waste dwelling on failures rather than putting that energy into another project, always amazes me. ... A setback is never a bad experience, just a learning curve."

Mackay's Moral: They say a word to the wise is sufficient, but I say a word from the wise is a gift.